I have installed docker on my centos6.5,but there always exists some problems saying that 'FATA[0000] Cannot connect to the Docker daemon. Is ‘docker -d’ running on this host? 'the result I got really astonished me ,because I have searched for the documentation about how to install the docker step by step on the website https://docs.docker.com/installation/centos/.

My teacher as well as tutor Mr.Zeng has told me to modify the network configuration, deleted the 172 network segments from the routing table, but you know actually this comes back to the configuration of network of my server.This may seem really easy ,however ,it will take you out of breath if you make some mistake even if you don’t realize it .I will come back when I figure out this issue.

Thanks ,I have tried what you told me ,but it did not work. I finally realized that the reason I got this issue was because I have taken my internet ip of 172.xxx.xxx.xxx.Because the docker itself uses this internet segment for utilization.